You should not breed a dog under one year of age, even if she goes into heat. A dog needs to be fully mature, both fully and mentally, in order to be an effective mother to a litter of puppies. If you breed an immature dog, she could have physical problems or become too stressed out mentally to care for the pups.
Female dogs are not ready to breed until they are somewhere between six months old and a year and a half old. If your dog doesn't show signs that she is ready to breed and she is still younger than a year and a half, she may not be mature yet. If she doesn't go into heat once she is past that age, you will need to consult a veterinarian if you are hoping to have her bred.
When you want to breed your dog, you'll need to be able to tell when she is ready. Otherwise, she won't be receptive to the male and the breeding process will not be successful. Female dogs exhibit some very apparent signs when they are ready to breed. If you follow the steps to notice these signs, you'll be able to pinpoint the right time to have her bred.
If the dog has been in heat previously, calculate the length of time since that last heat. Normally it takes at least four months for a female dog to go back into heat. However, this period can range between four and 14 months, depending on the dog's age, genetics, health and reproductive system.
Observe the dog's genital area. When a female dog is getting ready to go into heat, her vulva will begin to swell. If you check out the dog's rear end, it will be much more noticeable than usual.
Watch for signs of discharge. When a female dog is is going into heat, she will bleed from the vulva. The bleeding typically begins within a week of the vulva swelling. The discharge can range in color from deep red to milky pink or white. The dog will typically be fertile about 12 days after the bleeding slows and gets thinner and lighter.
Take note of how often the dog urinates. When a female dog is ready for breeding, she often urinates more frequently than normal. If your dog is begging to go outside more than usual, it could be a sign that she is in heat.
Watch for male dogs that appear to be very attracted to your dog. When a female is in heat, unneutered male dogs can sense it because there is a distinct smell given off by an ovulating female, and they will seek her out. If male dogs are hanging around your home or yard, or if they accost you when you are walking your female dog, it's likely that she is in heat.
If all of the other signs are present, expose the female dog to the male with which you want her to breed. If she is truly ready, she should stand for him willingly while he performs the act. If she is reluctant or wants to fight, you will need to wait another day or two before trying again.